TS 185 Piston Explosion

[Loydee]

Hi posting for a mate who has TS185 ER. We were out for a practise and his TS stops and kickstart is solid. Strip it down in the field and half the piston has exploded leaving tiny fragments all round the crank. Can he just flush out the crankcase and replace the piston (barrel is fine) or will those fragments have damaged the crankcase seal(s)? Thanks for your time people.

[pokey]

How good are you at Jigsaw puzzles?
 if your sure all the parts of the piston are out otherwise sure as shit a bit will end up un the bearings and stuff everything.
 on another point pistons just dont do that unless there be something wrong so id get that sorted  aswell.

 if its a complete shitter yeah just flush it out with the garden hose and then   some premix.  no gaurantee  something aint broke though.

[Freakshow]

Define exploding and where. did the skirt crack off or did you hole the piston and chew up the small end ?

[Loydee]

Yep, skirt blew off and made loads of minute fragments went down all around the side of crank webs, between them, -everywhere!

[pokey]

Skirts  do that when the clearance to the bore is too great and  its allowed to rattle (would have heard the piston slap) or its been consistantly over revved , most likely a combo of the two.

 Id measure that bore top and bottom and see if it wasnt time for an oversize and a rebore.

[Tim754]

And totally strip engine as it will be a waste of money to rebore then listen to it chew up its guts with all the tiny bits of crud still in there.

[Lozza]

Better question to ask yourself is why? As pistons are not in the habit of sponaneously combusting.

[Loydee]

Ok fellas thanks for all the input, general consensus seems a) Strip it and b) Figure out why. I'll pass these considered opinions on to my mate but reasoning why is a tricky one.Bike wasn't over rattly on top end he'd only been on it 2 mins and being a novice was dead easy on the revs.. Only good thing is bike was dirt cheap to start with! Thanks again.

[Freakshow]

probally been done well before his time on it. he just happened to be sitting on it at the time

[cyclegod]

Is the bike running pre-mix or is the oil pump still in play? The sudden stopping of the magneto crank bearing as it seizes has been known to shatter a piston skirt on the 185's (I have had 2 do this to me on mine)

[Lozza]

That can twist the flywheel end of the crank too if one has some rpm at the time CG.Gotta feel for the poor bugga being geed up on how much fun all this old bike caper is and having that happen after 2 mins